1. Field of the Invention
The present invention relates to a silicon carbide semiconductor device, and in particular to a silicon carbide semiconductor device having a gate insulating film.
2. Description of the Background Art
Patent Literature 1 (International Publication No. 2008/156674) discloses a VJFET (Vertical Junction Field Effect Transistor) using SiC (silicon carbide).
Although a JFET has a low ON resistance and can perform high-speed operation, it is generally difficult for the JFET to achieve normally-off characteristics. Thus, according to Non Patent Literature 1 (R. Rupp and I. Zverev, “SiC Power Devices: How to be Competitive Towards Si-Based Solutions?”, Mat. Sci. Forum, vols. 433-436 (2003), pp. 805-812), a cascode including two chips, that is, a SiC VJFET and a Si (silicon) MOSFET (Metal Oxide Semiconductor Field Effect Transistor), is used.
Since the device of Non Patent Literature 1 is configured using two chips (substrates), it has disadvantages such as increased size and increased manufacturing cost of a semiconductor device.